# A081093 (b-file synthesized from sequence entry) 1 3 2 7 3 31 4 127 5 3583 6 8191 7 131071 8 524287 9 14680063 10 1073479679 11 2147483647 12 266287972351 13 4260607557631 14 17591112302591 15 246290604621823 16 17996806323437567 17 1152917106560335871 18 2305843009213693951